During one particularly damp period during the season of the Golden Rain, the Great Tree was appearing very ill. Isolde set out to find the cause. She and the Ga'Hoolology Chaw flittered through the boughs, examined the colossal trunk, and poked around the roots. This surveying of the tree was no easy task. After several days and several inspections, Isolde found the first clue.
Little mushrooms of a kind Isolde had never before seen were growing in a crack near the roots. When Isolde touched one of the black pileus caps with her wingtips, a fine black powder spurted from them into the air. On a moonless night, she cut into the root beneath the mushrooms with the aid of a pair of modified Battle claws. To her horror and amazement, she discovered streaks within the heartwood of the root that glowed like fire in the night. With the color and intensity of hot coals from a forge, the streaks lit up Isolde's face. She cut along the root farther into the ground, and discovered that the streaks ran deep into the tree, zigzagging, she was certain, through much of the root system.
The young members of the chaw, after Isolde informed and showed them, had never seen anything like this infection before, some thinking it was the result of Nachtmagen.
The next night, Isolde and her chaw set out to find a cure for the great tree. The chaw split up into pairs and flew to various parts of the Southern Kingdoms, seeking knowledge from all the sage creatures of the land. While one pair (Polliane and Hildeth) went to the Shadow Forest in search of Aude and another (Elva and Sanders) went to the Forest of Tyto in search of the Dark Sisters, Isolde and Marduk head from Ambala to speak with the Bald Eagles, who always seemed to know the latest happenings in the entire kingdom. The three groups would reconvene in Ambala to discuss their findings.
In the Forest of Ambala, the eagles reported to Isolde and Marduk that several stands of trees in Ambala had been killed in the last year by a yet unknown malady. It was now clear - black fire was back in the Southern Kingdoms.
The whole chaw soon called on the Dark Sisters again.